Rheostat.



T. RHODUS.

RHEOSTAT.

APPLICATION FILED luNE 23.1917.

1 ,247,009. Patented Nov. 20, 1917.

THOMAS RHODUS, OF CHICAGO, ILLINOIS.

nHEosTA'r.

Specivcation of Letters Patent.

Patented Nov. 20, 191 7 Application led June 23, 1917. Serial No.176,463.

To all whom t may concern.'

Be it known that I, THOMAS RHonUs, a citizen of the United States ofAmerica, and a resident of Chicago, in the county of Cook, State ofIllinois, have invented certain new and useful Improvements in'Rheostats, of which the following is a specication. The yinventionrelates to that type of adjust-ablel rheostat which constitutes thesubject matter of my prior Letters Patent...No. 1,053,219, datedFebruary 18, 1913, and' No. 1,154,728, dated September 28th, 1915, andthe present improvement has for its various objects To provide astructural formation and combination of parts in the wire woundresistance element of a rheostat, involving a plurality of subwindingsconnected in series and having progressively different electricalresistance, the a'rangement being adapted to introduce aY multiplestep-bystep -increase or decrease of resistance in the circuit-of therheostat as the movablecontact member is moved in one or the otherdirection upon and in contact with said resistance element. To provide aduplex arrangement of the wire windings of the resistance element of arheostat, with the respective divisions of saidV windings connected inmultiple in the electric circuit of the rheostat, and in connectiontherewith the provision of a movable contact member of the duplex typewith the respective contacting ends of said contact member individualtoand making contact with the corresponding duplex windings of theresistance element aforesaid. The advantages resulting from thedescribed arrangement being a division of the current to the duplexwindings with less liability to fusion of the resistance element.

To provide a simple and effective structural formation-and arrangementof parts by means of which the movable contact arm or arms of anadjustablerheostat, are yieldingly connectedto a central operating shaftin a durable, eficient and economical manner, all as will hereinaftermore fully appear.

The accompanying drawing is an elevation of a rheostat having thepresent improvement ap lied, the central operating shaft and thelnclosing casing being shown in section.

.Referring to the drawing, 1, designates a base orspider providing asupport for the oriced inclosing casing 2, the insulating rail orsupport 3, and other portions of the rheostat, hereinafter described indetail.

4 designates the supporting core of the stationary resistance element ofthe rheostat.4 Said core is of the usual ring form and havingoverlapping ends by which it is secured to a supporting bracket 5 on theinsulating rail 3 aforesaid.

6 designates the series of fiat, open spiral windings of the stationaryresistance element, wound upon the core aforesaid. In the presentimprovement said spiral tindings comprise a plurality of groups orsubwindings-7, 8, 9 connected in series, with each group havingprogressively different electrical resistance, and attained by anincrease or decrease in the cross-sectional area of the individual`convolutions of a subwinding, as lshown in the drawing.

In the preferred type of the present invention, two spiral windings 6are applied to the ring form core 4 in opposed relation to each other,and connected in multiple' in the circuit of the rheostat, as shown.

10 designates a centrally arranged 4shaft revolubly mounted on theinsulating slab 3 aforesaid, in any usual manner, to constitute theoperating member of the rheostat. 11 designates a cross-head preferablyof the H shape shown, liXedly secured to the aforesaid operating shaft10, and formed with a pair of orificedguide flanges 12.

13, 13, designate counterpart sliding bars arranged to have slidingmovement in the guide flanges 12 aforesaid, and located at oppositesides of the shaft 10 and in approXimately parallel relation toeachother.

14, 14, designate counterpart contact rollers journaled in any Suitablemanner to the 'outer ends of the aforesaid sliding bars 13, 13, andadapted to have rolling contact with the inner faces of the resistancewindings 6 aforesaid; one of the bars 13 with one of the contact rollers14 forming a working contact member. In the construction showntherollers 14, 14 have electric connection /in common kwith thecross-head 11, which in turn has electric connection with'one side orwire of the circuit of the rheostat.

15, 15 designate springs adapted to impart outward movement to thesliding bars 13, 13 and. the associated contact rollers 14, 14aforesaid.

In the preferred form of the present ine.`

vention shown in the drawing, the two groups of sub-windings are soarranged in the electric circuit that the sub-windings of the respectivegroups having thelowest resistance, will be disposed next adjacent tothe respective line.wires of the circuit so as to remain longest in saidcircuit. rIhe described arrangement is intended for use with the threewire system of electric wiring and in connection'with twin electricalappliances in which an' increase in current in one appliance is requiredwith a simultaneous decrease in current to the companion appliance, andvice-versa.

Having thus fully described my said/ invention, what I claim as new anddesire to secure by Letters Patent, is

l. In a rheostat, the combination of a resistance element formed ofgroups of subwindings of resistance wire, arranged in series, the wireof one group differing in cross-sectional area from the wire of anothergroup, a contact member making contact upon said resistance element, andmeans for effecting movement between said parts, substantially as setforth.

2. In a rheostat, the combination of a curved resistance elementcomprising a plurality of resistance windings arranged in opposedrelation and connected in multiple in the circuit, contact membersindividual to and making a contact upon said windings, and means foreffecting movement between the parts, substantially as set forth.

3. In a rheostat, the combination of a curved resistance elementcomprising a plurality of resistance windings arranged in opposedrelation and connected in multiple in the circuit, each of -saidplurality of windings comprising groups of sub-windings arranged inseries and having progres- 1 s ively dierent electrical resistance,contact members individual vto and making contact upon said windings,and means for effecting.

ythe circuit to the line wire terminals, contact members individual toand making contact on said windings, and means for effecting movementbetween the parts, substantially as set forth.

5. In a rheostat, the combination of a curved resistance elementcomprising a plurality of resistance windings arranged in opposedrelation and connected in multiple in the circuit, contact membersindividual to and making contact upon said windings and mounted on acommon carrying head, and means for imparting a turning movement to saidhead, substantially as set forth.

6. In a rheostat, the combination of a curved resistance elementcomprising a plurality of resistance windings arranged in opposedrelation and connected in multiple in the circuit, Contact membersindividual to and making contact upon said windings, a cross-headadapted to support said Contact members in spaced relation, springs formoving said contact members, and an operating shaft connected to saidcross-head intermediate of the aforesaid contact members, substantiallyas set forth.

Signed at Chicago, Illinois, this 21st day of June, 1917.

THOMAS RHODUS.

